Check engine light flashing intermittently car jerking on 2003 Mazda Protege

I just bought a 2003 Mazda Protege with 140,000 miles. While driving it home the car started jerking a bit and the check engine light came on. I stopped for a bit and started driving again with no problem and then about a half hour later it started jerking again and the light started flashing. I stopped again. When I started to drive again the light remained on (but not flashing) and the car was jerking subtly. The O2 sensor was replaced right before I bought it. What is the likely problem?

by in Fargo, ND on September 25, 2009
7 answers 4 comments
ANSWER by on September 25, 2009
So many things could be responsible for making the engine run poorly it is hard to speculate without being able to drive the vehicle or perform some tests first hand. There is a service bulletin from Mazda that may apply 01-028/05 regarding a stuck EGR valve. If the Check Engine light/Service Engine Soon light illuminates while you are driving, the car's on board computer sees a fault in the engines management system that is causing an excess amount of pollutants to be emitted from your car. This could result in engine damage if left neglected. Some problems that can cause the Check Engine light to stay on may take two "drive cycles' to complete before illuminating the Check Engine Light. The computer sees a problem and looks for an identical set of circumstances to occur to confirm that it has indeed seen a problem before turning on the light. A Check Engine light that continually flashes while you are driving is serious and is a sign that the computer sees a problem that seriously risks damaging the catalytic converter which may result in an expensive repair or even may cause a fire! Diagnostic codes are stored in the vehicle's computer and can be retrieved using a scantool that communicates with the computer in your car. We have in our Repairpal website an encyclopedia with in depth articles about computer, and computer control systems, emission and driveability problems.
COMMENT by on August 25, 2010
Most probably the EGR is stuck open, use a scan tool if these codes pop up DTCS P0300/PO401 replace the EGR and have the injectors cleaned Mazda TSB021-028/05 Check with the dealer it maybe under warranty
ANSWER by on May 21, 2010
i have same problem...
ANSWER by on August 27, 2010
Have had the same problem but Catalyst was replaced before second O2 sensor was replaced and it fixed it on a 2002 Protege. Second O2 sensor need a good catalyst ($$$) to send good voltage to computer. Actually, I work with a problem likely to be EGR valve at IDLE...
COMMENT by on September 30, 2010
be aware that if there was an issue bad enough to cause your cat to fail you should concider replacing the rear O2 sensor because it may have been damaged also
ANSWER by on September 30, 2010
do a tune up .. you just got the car and you cant be sure it was done or done properly It all starts there .. fuel filter, air filter, plugs & wires, pcv valve... bad plugs and wires can cause issue after the car is hot when there was no issue when cool .. also if the engine isnt burning the fuel/air properly all the other systems have to try and compensate maybe even get clogged or damaged
COMMENT by on February 19, 2011
for a mazda protege 2003 in my expericence, if you have rough idle then just look at your EGR valve. Just disconnect it and look if it make 0 - 1000 rpm and rough idle, if it does not then replace your egr valve for the newer model...
ANSWER by on November 03, 2012
Check the air intake hose for cracks.the one from your air filter to intake.I had same problem on 2 proteges and both jerked like crazy and had a miss in it idling,and gas milage went down.common problem.duct tape works fine til u get a new one
COMMENT by on March 19, 2014
Thanks Shawn. Your description of my problem was spot on. My air intake hose had a large crack. Relaced the hose with a Dorman air intake hose from Amazon. Cost me like $26. It was an easy job to replace it. Once again thank you and to all who take the time to post. You all help and make a difference!
ANSWER by on March 22, 2013
I bought a 95 mazda protege about 2 months ago, the guy who sold it to me didn't tell me about the check engine light being on. When he finally did tell me about it, I took it to auto zone to get scanned and they told me it was the egr valve. I took it back home and being the cheap person I am just took it apart and cleaned it out, drove it around for a bit and the light went off and hasn't come on since. But it is interesting to know more about how these vehicles work. Also sounds like something is restricted.
ANSWER by on June 27, 2015
I had a similar experience on my 02 Protege5 with 170k. Check your air intake and make sure there are no leaks. Then, run a fuel system cleaner to clear up carbon buildup clogging the system -see fuel system cleaner tests on youtube. Use the full bottle usually for 15-30 gal, in one tank of gas for max concentration. This worked for me & permanently shut off the check engine light.

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